Diseased grass facts

July 6, 2011

Generally, diseased grass is difficult to recognize, because many signs of infections are in fact indicators of inadequate cultural practices used for the lawn. For instance, yellow and brown spots on the grass can be just the effects of too much fertilizer. To apply the right treatment and approach, it is vital to distinguish whether it is about diseased grass or poor gardening procedures.

Almost all pathogens and fungal spores can be spotted, so the best thing you can do is to monitor and note any changes related to your lawn condition. A good option is a log book where you write about mowing, watering, dethatching, fertilizing, pesticides, weather conditions and other noticeable signs.



Sometimes fungal disease can be avoided by watering only in the morning. You should also know that warm moist weather can cause leaf spot in the spring, while cool weather can lead to rhizoctonia yellow patch appearance. Improper mowing such as cutting the grass to short or using dull blades can also lead to fungal infections.

Even if it is hard to say your lawn is facing a disease, there are two major signs that show this: spots and discoloration.

  • Spotty grass blades

The presence of spots is a symptom of diseased grass. How can you tell? Go on the lawn in the morning while the dew is still there and search for matted, white fungal structured that look like cotton candy. Of you find such fungal growths on the grass, it means you lawn is infected. Examine and note the color and size of the spots on grass blades in order to determine what is the right fungal disease.


  • Discolored patches

Discoloration is another symptom of diseased grass, no matter if the discolored patches are small or large. In the moment grass areas do not feature uniform green color, it is possible the lawn is infected with rhizoctonia blight, sclerotinia dollar spot or summer patch. When you see circular discolored areas of the grass, write down the weather conditions and if you used fertilizers or pesticides recently as these can be the discoloration causes.

Make note of every signs of spots, discoloration, wilting and growth problems, as well as the time of day, date and weather conditions. There is usually a pattern for the appearance of fungal disease. If you keep track of the time and conditions leading to diseased grass in your yard, you can apply fungicides before it happens based on the information from the previous year.

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